There are 8 stages to meiosis. The first stage is prophase 1. During this stage the chromosomes will line up with their corresponding homologous chromosomes and form a tetrad. Next is metaphase 1 in which the centrioles attach to the chromosomes and they line up in the center of the cell. Anaphase 1 is the stage when the centrioles pull the chromosomes toward opposite ends. During Telophase 1 two different cells. Then Meiosis 2 starts with Prophase 2. The chromosomes are loosely organized and the centrioles are moving into place. Next during Metaphase 2 the chromosomes line up in the ceter of the cell. After that is Anaphase 2. The sister chromatids pull toward opposite sides of the cell. Finally is telophase 2 which results in 4 haploid daughter cells.
Mitosis and Meiosis are similiar and different in many ways. Mitosis results in 2 genetically identical diploid cells, whereas meiosis produces four genetically different haploid cells. In meiosis all the cells are different but in mitosis the cells are identical.
A karyotype is a picture of chromosomes that scientists can use to see what is inside a human cell. The scientists cut out the chromosomes from the photographs and group them together in pairs.
Non-Disjunction is the failure of homologous structures to segrate or to seperate during and after meiosis. Examples of non-disjunction are down syndrome, turner's syndrome, and klinefelters syndrome.
Meiosis
Links:http://www.biostudio.com/d_%20Meiosis.htm (Meiosis animation)
http://www.biostudio.com/d_%20Streisinger%20Model%20of%20Mutation.htm (mutation animation)
http://www.biostudio.com/d_%20Meiotic%20Nondisjunction%20Meiosis%20I.htm (Nondisjunction animation)
I used the textbook pgs 275-278, 341, 352-353